This proposal is a request for financial support for a half-day symposium on The Chemistry of Mutagenesis to be presented at the American Chemical Society National Meeting, Washington DC Aug. 28-Sept 1, 2005. The topic of this symposium will be the mechanisms by which DNA polymerase-catalyzed replication of carcinogen-damaged DNA leads to mutations. This topic is extremely important because it is the ultimate cause of mutagenesis and ultimately cancer. Recently there has been a large amount of research into replication of damaged DNA by the Y-family bypass polymerases. Much of this work has focused on the structure of the polymerases and to evaluate the substrates of each polymerase. More recent work, lead by the "invited speakers", has been to understand the mechanism of why certain nucleotides are inserted opposite damaged DNA. The invited speakers are chemists who use the structural and biochemical properties of the systems to elucidate the reaction profile. Each of the speakers has an international reputation in their areas of expertise. The goal of the symposium is to bring together experts in the chemical mutagenesis field so that they will be able to educate the scientific community concerning these enzymes with the hope of attracting new investigators to the field.